This invention relates in general to differential gear mechanisms and in particular to a differential which is selectively lockable so as to prevent differentiation.
Differential gear mechanisms, commonly referred to simply as differentials, are well known devices which are frequently used in the drive trains of most vehicles. The differential is usually connected between an input driving shaft (typically a drive shaft from the vehicle engine) and a pair of output driven shafts (typically a pair of axle shafts connected to the vehicle wheels). The differential distributes torque from the input shaft equally to the two output shafts, while permitting such output shafts to rotate at different speeds under certain conditions. As a result, torque is supplied to both wheels of the vehicle as it negotiates a turn, while permitting the outside wheel to turn faster than the inside wheel.
In a conventional open differential, the movements of the various internal components of the differential are not restricted in any significant fashion. Thus, the differential functions in the desirable manner described above under most circumstances. However, when one of the wheels of the vehicle loses traction with the ground, such as can occur on wet or icy surfaces, the differential will reduce the amount of torque supplied to the other wheel. Consequently, the vehicle can become immobilized.
To prevent this from occurring, some differentials are provided with an operator actuated locking device. When actuated, the locking device completely restricts the movement of the internal components of the differential, thereby providing full torque from the engine to both wheels. At the same time, however, both wheels are driven at exactly the same speed. Thus, locked differentials are not well suited for use on non-slippery surfaces Many different devices are known for selectively locking the differential for operation in this manner.